Nanocrystal device layers, such as silicon nanocrystals or germanium nanocrystals are used in semiconductor processing. For example, nanocrystal device layers have been widely used in Non-volatile memory (NVM) devices. NVM devices have achieved widespread adoptions for code and data storage applications. The use of nanocrystal device layers as the storage medium has demonstrated fast injection programming, fast tunnel erase into the gate, and robust data retention.
In the fabrication of devices, the nanocrystal layer is patterned. Patterning selectively removes portions of the nanocrystal layer in order to obtain the desired structure. However, conventional patterning processes have been ineffective in completely removing desired portions of the nanocrystal layer. This leaves nanocrystal remnants on other device layers or substrate. Such nanocrystal remnants create problems for subsequent processes. For example, nanocrystal remnants on the substrate or on device layer hinder uniformity of ion implantation for doping poly gates or substrate to form source/drain regions of transistors. This may undesirably result in high n+/p+ unsilicide poly resistance, high bitcell contact resistance, as well as large resistance variation across the wafer.